Income Taxes (Details 2)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes
Tax at statutory federal income tax rate (as a percent)	34.00%	34.00%	34.00%
Increases (reductions) in taxes resulting from:
State income taxes, net of federal benefit (as a percent)	1.20%	1.50%	1.80%
Change in valuation allowance (as a percent)		0.60%
Domestic manufacturing deduction (as a percent)	(3.80%)	(2.10%)	(2.50%)
Capitalized acquisition costs (as a percent)	3.60%
Effect of foreign operations (as a percent)	5.90%	(0.70%)	(0.50%)
Foreign dividend income (as a percent)	(1.50%)		(2.90%)
Tax-exempt interest (as a percent)	(0.40%)	(0.20%)	(0.20%)
Changes in unrecognized tax benefits (as a percent)	(0.30%)	0.30%	0.60%
Stock option compensation (as a percent)	2.50%	0.30%	0.70%
Research credit (as a percent)		(1.00%)	(1.10%)
Other (as a percent)	(0.40%)	0.90%	0.20%
Effective income tax rate (as a percent)	40.80%	33.60%	30.10%